Laser Cutting Characteristics Using High-speed Camera of 75-㎛ Thick Stainless Steel Foil in Lightweight Fuel Cell Applications

The automobile industry is attempting to suppress carbon emissions by developing fuel-cell electric vehicles (FCEVs), which are pollution-free vehicles. Because the fuel cell stack is manufactured by stacking numerous thin parts, reducing the thickness of each part to reduce the weight and volume is important. Therefore, precise cutting of the thin plate material is required. In this study, an IPG YLS-5000 fiber laser model, a 5-kW single-mode fiber laser with a beam size of 30 ㎛, was used to cut a thin plate STS316L material with a thickness of 0.075 mm. The cutting process was studied using a 650-nm wavelength filter and a high-speed camera with a frame rate of 30,000 frames per second. This study involved the investigation of various research components, such as the process from the formation of melt to hardening, the amount and divergence angle of the fume, and the size and speed of the spatter. In the process of forming the molten pool, shaking of the molten liquid, merging between the molten liquid, and sticking of the molten liquid were confirmed. This study will be helpful for future research on the quality improvement of laser cutting for very thin metal sheets.